The civilization that flourished in the Indus Valley and built Mohenjo-Daro around 3000 BC was a rival of its better-known Sumer and Egyptian equivalents. Built around 2600 BC in present-day Pakistan, Mohenjo-daro was one of the early urban settlements in the world. It is sometimes referred to as “An Ancient Indus Valley Metropolis”. It has a planned layout based on a grid of streets, which were laid out in perfect patterns. At its height the city probably had around 35,000 residents. The buildings of the city were particularly advanced, with structures constructed of same-sized sun dried bricks of baked mud and burned wood. Mohenjo-daro and the Indus Valley civilization vanished without a trace from history around 1800 BC until discovered in the 1920s. It was made a UNESCO World Heritage site in 1980.